Science talk:Math Exam Resources/Courses/MATH101/April 2013/Question 02 (b)

I would like to see an explanation of why the r term is what it is - perhaps rearranging the sum a bit so that its clear what the ratio is.

Also, I would like to see a solution that does a change of variables to get the starting index to 0 and then attempts to evaluate the sum.

The answer itself however is fine.